Adventures along the Umpqua River and the Oregon Coast

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Speaking of Dungeness……

This post is reprinted through the gracious permission of the South Slough National Estuarine Research Reserve at Charleston, Oregon. It was posted on their Facebook page awhile back. Also contributing were the Oregon Dept of Fish and Wildlife and the Dungeness Crab commission. Check them out at the bottom of the article. Thanks, South Slough Estuary!

Field Note Friday, Did you Know……..

That the Dungeness crab was named after a small fishing village on the Strait of Juan de Fuca in Washington state?
That Dungeness crabs have been harvested commercially along the Pacific Coast since the late 1880’s?

Dungeness crab (Cancer magister) are crustaceans, with an exoskeleton or shell. They have eight walking legs and two claws. Their lifecycle begins when a sexually-mature male crab mates with a newly-molted, soft-shelled female crab in the late spring/early summer months. The eggs are fertilized when they are fully developed and ready to hatch in the late fall/early winter. A female crab can carry up to 2.5 million eggs in the protected area under her abdomen

How a Crab Molts…
When the crab is ready to molt, it swells with water and splits, the SUTURE LINE on its back. The new shell forms under the old one. Once this happens, the crab is ready to molt.
After breaking open the suture line, the crab backs out its shell. After the crab molts,
the new cuticle (or shell) is very soft. The newly molted crab takes up water to fill the new soft shell and get larger. The new shell takes 2-4 days to harden.

The Dungeness Crab: Cancer Magister
Carapace width can reach up to ~22cm
They live up to ~10 years!

Crabs are sexually mature and active breeders after their second year and grow to the legal harvest size (6 ¼” across the shell back) in roughly four years. By not harvesting sexually mature but undersized male crabs so that they can breed with female crabs (which are never harvested), the reproductive capacity of the population is protected. Dungeness crab can live in excess of 8 years and reach a size of 9-plus inches.